Scroll type machines are becoming more and more popular for use as compressors in both refrigeration as well as air conditioning applications due primarily to their capability for extremely efficient operation. Generally, these machines incorporate scroll members having a pair of intermeshed spiral wraps, one of which is caused to orbit relative to the other so as to define one or more moving chambers which progressively decrease in size as they travel from an outer suction port toward a center discharge port. Some type of power unit is provided which operates to drive the orbiting scroll member via a suitable drive shaft. The bottom or lower portion of the housing which contains the scroll members normally contains an oil sump for lubrication of the various components of the compressor.
Scroll machines can be separated into two categories based upon the power unit which drives the scroll member. The first category is scroll machines which have the power unit located within the housing along with the scroll members. The housing containing the power unit and the scroll members can be open to the environment or it can be sealed to provide a hermetic scroll machine wherein the housing also contains the working fluid of the scroll machine. The second category of scroll machines is scroll machines which have the power unit separate from the housing containing the scroll members. These machines are called open drive scroll machines and the housing which contains the scroll members is normally sealed from the environment such that the housing also contains the working fluid of the scroll machine. The power unit for these open drive scroll machines can be provided by a drive belt and a pulley system, a gear drive system, a direct drive system or any other type of drive system.
The above categories of scroll machines can each be further subdivided into two additional categories of whether the scroll members are positioned vertically which is most common with the hermetic compressors or whether the scroll members are positioned horizontally which is most common with the open drive type of scroll machines.
Both the vertical and the horizontal positioned scroll machines perform satisfactorily in their respective market. Typically the power unit for these scroll machines is a single speed drive or a more expensive variable speed drive system. Various applications for scroll machines would benefit if a scroll machine had a low speed capability and a high speed capability. These two speed scroll machines could be produced at a cost significantly lower than the variable speed scroll machines and thus inexpensively satisfy the market for the applications which would benefit from a scroll machine having a low capacity capability and a high speed capability.
The present invention discloses a unique two speed drive system for an open drive horizontal scroll machine which functions to operate the scroll machine at a low speed capability when the scroll machine demand is low and a high speed capability when the scroll machine demand is high. A unique planetary gear system is positioned between the power unit and the drive shaft of the scroll machine to provide the two speed capability.
Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.